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Harddisk Coat Hooks

What do you do with your old harddisks? Keep them untill there are no more IDE cables available? And then throw them away or give them to a company that safely destoys the harddisk, so nobody could possibly ever recover the files from that disk?

It's obvious: take it apart and make something out of the hightech disk inside. But I needed coat hooks, so i decided to use the harddisk body to make them.

The body is made of aluminum, so it's very easy to work with. A larger amount of harddisks also makes quite a lot of aluminum, that's probably worth quite a bit of bling-bling. OK, we don't want to sell it. Let's get started, grab an old disk from your parents stack of backup disk.

Step 1: Take Off the Top Cover

Also grab a kitchen knife or some other knife and a T9 Torx screwdriver. You might need a T7 screwdriver for some inner screws as well. Unveil the screw under the sticker at the disk head. Take out all the screws so you can take off the top plate.

Step 2: Open the Disk

You have just lost the warranty for your disk, but it's probably too old anyways. Take out all the screws here too, and disassemble the drive. There are two very strong neodymium magnets at the head assembly, don't hurt yourself when taking these apart.

Step 3: Disassembly

You can harvest two neodymium magnets and two very precise bearings from the head assembly and the drive motor, which is still on the disk body. The disk (there might be multiple disks stacked inside) is very tempting too, but I don't have any idea what to do with it, yet. We also want to take apart the drive assembly, but let's disassemble the backside first.

Here is a tutorial how to recover the bearings: http://rbteam.wordpress.com/2012/04/28/recover-bearings-from-old-hdd-for-robot-building/

Step 4: Disassemble the Backside

Unscrew all the screws from the back side and take off the circuit board.

Step 5: Take Out the Main Bearing

We want to take out the main bearing, which is tight fitted in the disk center. Find a hammer an something to punch the bearing through the disk body from the back side. A nail or something should be fine, but don't hurt yourself. You also need some wood or something to lift up the harddisk body, so that the bearing can fall through on the other side. Also don't damage the kitchen table.

Here is an PDF from HGST which details the design of a harddisk bearing (don't care for fluid dynamic bearings for now): http://www.hgst.com/tech/techlib.nsf/techdocs/089C4B963AEE9A6F86256D340075052F/$file/FD_White_Paper_FINAL.pdf

Step 6: Prepare Threads

So now we have the raw aluminum body with a nice hole in the middle and these steampunk colis around. There might be some rubber parts to take out, and a cleaning pad (?), which cab be removed with some benzine (or suck some gasoline from you brothers bike). The hole has probably a diameter between 10 an 12 mm, that's perfect for an M12 thread. So you need dies. Find some or ask your parents to buy some, they certainly do. There is a second hole from the head assembly, which is on exactly that position on every drive, so it's perfect for n additional hook. We want to drill that for a M6 thread.

Step 7: Drilling

Before cutting he thread we want to re-drill the hole for the proper width. An M12 thread needs a size 10 hole, see ISO 965: http://en.wikipedia.org/wiki/ISO_965 Widen the hole if necessary, be sure to - Don't hurt yourself! - Don't damage the kitchen table! - Wear safty glasses!

Step 8: Cut the Threads

OK, cut the threads. Be careful when you start cutting, don't hasitate. Make sure that you cut straight down and don't cant the die. Also pre-drill the smaller hole with a size 5 drill and cut an M6 thread.

Step 9: Mounting Hole

I intend to mount the hooks with one screw in the middle. So I need to mark the spot and punch it with a nail or something, so that the drill gets a focus point and does not slip. I am using a size 5.5 drill. Don't damage the kitchen table!

Step 10: The Hooks

We now need the hooks. We will cut them from a threaded rod. Grab an M12 threaded rod from the garage and a metal saw. I have use the cheaper zinc-coated ones, but you might be lucky to find the stainless steel ones, which are probably nicer in the end. Cut off some pieces of about 7-8 cm length.

Step 11: Smoothing the Hooks

The thread is too coarse to be used for clothes. We want to smooth it, so we need:

Step 12: Smoothing

Wear safty glasses! Fast rotating power tools and metal machining are a PERFECT combination to injure your eyes with metal chips. Place the drill on a solid surface, turn it on to a medium speed (clockwise) and use the file to take off the sharp edges. Also smoothen the cutting edge on the end of the rod.

If you are done with the file, carefully use the sandpaper. You are in direct contact with the power tool now, so the chances to get injured are increasing.

In the end use some steel wool to even more smooth the edges. Chances to get injured are increasing even more, because the steel wool WILL get entangled in the thread/drill, so be very careful.

Do that for all but the last 2 or so centimeter of the rod, where we want the thread intact.

Step 13: Test Fitting

A closer look at the result will reveil some chippings from the zinc coating, but that's OK to me. This would not happen with a stainless steel rod. It's smooth enough for the architects silk scarf, but also has some grip, so that the coats or other clothes don't just slip off the rod. Test-fit your assembly.

Step 14: Done

That's it. Use some glue, some nails or screws to hang them up. Here are some action shots. Have fun.